Maria (Mary) Ramirez Terronez was born in San Luis Potosi, Mexico, in 1918 to Adelida Gutierrez Ramirez and Dionisio Ramirez, the third oldest of fourteen children. She was four years old when her father was recruited to work for the Rock Island Railroad in Davenport, Iowa. The rest of the family joined him one year later in 1923, when Mary Ramirez was five years old. They settled in the barrio known as Cook's Point near the railroad tracks in southwest Davenport. Ramirez attended Davenport schools where she completed the sixth grade after which she stayed home to help her mother cook, clean, and look after her siblings.

In 1936 she married Felipe Bravo Terronez, a railroad worker, who was originally from Mexico and had grown up in Silvis, Illinois. The couple had six children: Virginia (born 1933), John (born 1938), Phyllis (born 1940), Irene (born 1944), Georgia (born 1949), and Randolph (born 1955). Mary Terronez became a U.S. citizen in 1962.

Terronez was a community activist most of her adult life. She served as an interpreter and liaison between the Spanish-speaking community and the schools, sheriff's department, U.S. Immigration Service, business owners, medical doctors, and welfare agencies. She was a spokesperson for Cook's Point residents during their forced relocation in 1952, when the barrio was closed down. She supported the grape boycott campaign by picketing local supermarkets and also cooked for a reception for Cesar Chavez in 1969 when he attended a grape boycott rally in Davenport.

From 1971-1974 she was the job coordinator for the Area Board for Migrants; in this position she worked with the Spanish-speaking community in the Quad Cities, interviewing job seekers, contacting employers, and matching job seekers with job vacancies. Terronez later worked with the Muscatine Migrant Committee and served as a teacher's aide for the Davenport Community School District where she raised funds for new playground equipment at Jefferson Elementary. In 1976 she completed her GED and continued her education at Palmer Junior College where she graduated with an AA degree in 1980; she was honored with a placement in Who's Who Among American Junior College Students.

Terronez was involved in many organizations including the League of United Latin American Citizens (LULAC), the Mexican-American Committee on Education, and the Visiting Nurses Association. Terronez received recognition from institutions including the University of Iowa Chicano-Indian American Student Union, the American Institute of Commerce, and the State of Illinois. She was named KRVR radio's "Quad-Citian for the Day" in April of 1983. In 1997, Terronez attended President Clinton's second inauguration in Washington, DC. Mary Terronez passed away in 2009 at the age of 91.